Under large populations, this happened when the mutant's relative fitness was higher with lower proportions of its type in the population, i.e. when mutants did relatively better among residents than they did between them (\(d/b<c/a\) ). In this limit, the selection dynamics are completely characterized by these ratios, as was already noted in [1]}. Increasing population size guaranteed that both mutants and residents interacted less frequently with residents in the initial steps of the fixation process, and therefore the increase on the number of individuals to be replaced was compensated by the higher replacement probabilities.
